Vancomycin is a tricyclic glycopeptide antibiotic that is effective against gram positive cocci. In the present study we have evaluated the influence of age on its disposition. Comparison of the mean data obtained from 6 young and 6 elderly volunteers shows that the half-life of vancomycin may be significantly longer in the old and creatinine clearance may not be the only determinant in its elimination. Renal clearance (RC) appears to be reduced. However no significant correlation is apparent between creatinine clearance and RC. These data suggest that dosage adjustments may be necessary in the elderly.